import org.junit.Test;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class JunitDemo {


    @Test
    public void demo() {
        int[] a = {3,2,1};
        int[] b = new int[2];
        Arrays.sort(a);
        System.out.println(Arrays.toString(a));
        System.arraycopy(a,0,b, 0, 2);
        System.out.println(Arrays.toString(b));
    }

    @Test
    public void demo2() {
        Set<Integer> set = new HashSet<>();
        set.add(2);
        for (Integer integer : set) {

        }
    }

}
